ok, I was just playing and I decided to have a bit of fun and turn my amp up a little over half way and play harmonics.

and I found a few of the really sweet spots

12th fret G D and A

7th fred B and E

well I was playing these and my whole house was shaking and then all of a sudden I heard this metallic twanging, and I was wondering if that would be my amp blowing or what?

I turned it down and played normally, but I can't tell if there is a difference in sound or no.

Do you think my amp is blown?
If your amp was blown it wouldn't be playing normally.

So look for another explanation.
A recent study shows that 92% of all teenagers have moved on to rap music.
Put this in your signature if you are one of the 8% who stayed with the real music.
This happened to one of the amps I was playing on a while ago. It should play okay in the short run, but have it checked out at a repair shop.